Koadjuthen was formerly part of the German Empire. In the German Empire, the place was called Coadjuthen.
The place is now called Katyčiai and belongs to Lithuania.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Koadjuthen | German Empire | Tilsit | before the Versailles Treaty |
| Katyčiai | Lithuania | Pajėgiai | after the Versailles Treaty |
| Coadjuthen | German Empire | Heydekrug | 1939 |
| Katyčiai | Soviet Union | Pagėgiai/Pagegjaj | 1945 |
| Katičjaj | Soviet Union | Pagėgiai/Pagegjaj | 1945 |
| Katyčiai | Lithuania | Šilutė | 1992 |